1. Field of the Invention
This invention relates to an improvement in protecting the refractory lining of a metallurgical furnace, more particularly to the injection of liquid hydrocarbons through ports or tuyeres in such a furnace to discharge the hydrocarbons toward selected portions of its refractory lining.
2. Description of the Prior Art
With the advent of modern oxygen steelmaking processes in which pure oxygen is introduced into molten iron to refine it, considerable attention has been given by workers in the art to improving the life of the consumable refractory lining used in steelmaking furnaces. Much of this attention has been devoted to increasing the resistance of the refractory brick against chemical and physical erosion associated with oxygen steelmaking processes. While this effort has been generally successful to the point that many hundreds of heats may be processed during a single campaign on the lining, still further improvement in lining life has been sought by treating the refractory lining during the course of the campaign. Such treatments, however, generally have been confined to supplementing worn areas of the lining with added refractory material at a time when the furnace is not in actual use.
One popular method of lining supplementation is called "gunning". This technique involves the spraying of a refractory slurry on the worn areas of the lining by means of a pneumatically-operated spray gun. The use of "gunning" has increased lining life but it brings about some inefficiencies in furnace usage because the operation is time consuming and must be carried out between heats when the furnace is empty.
A further method of lining augmentation is described in U.S. Pat. No. 3,663,339 which is said to be an improvement in conventional "gunning" practices. This patent describes a boom which is insertable into the furnace and has secured to its inserted end a container carrying pulverulent refractory material. The container also includes an explosive charge which, when detonated, propels the refractory material against selected portions of the refractory lining. While the operation may be carried out with the furnace interior at elevated temperatures, the procedures described in U.S. Pat. No. 3,663,339 are, like "gunning", suitable for employment only when the vessel is empty. This means, of course, that the familiar operating cycle used in the basic oxygen top-blowing process, for example, must be modified to accommodate an extra operation.